1. Field of Invention
The present invention relates to a chemical-mechanical polishing device. More particularly, the present invention relates to a wafer carrier structure for a chemical-mechanical polishing device.
2. Description of Related Art
Chemical-mechanical polishing is one of the principal techniques for global planarization. Chemical-mechanical polishing is a physical process of grinding using a polishing wheel with the assistance of a suitable chemical reagent so that all uneven profiles on a silicon wafer are universally flattened.
FIG. 1 is a schematic side view of a conventional chemical-mechanical polishing device. FIG. 2 is a schematic top view of the conventional chemical-mechanical polishing device shown in FIG. 1. As shown in FIGS. 1 and 2, the chemical-mechanical polishing device includes a polishing table 100, a wafer carrier 106 (alternatively called a polishing head), a polishing pad 102 and a slurry-supply pipe 110. The wafer carrier 106 is used to hold a wafer 104 and comprises a holder 105, a hole (not shown) to apply suction to the wafer 104 and a retaining ring to support the wafer 104. The polishing pad 102 is placed on the polishing table 100 and the slurry-supply pipe 110 are used to deliver slurry 110a to the polishing pad 102. To carry out a chemical-mechanical polishing, the polishing table 100 and the wafer carrier 106 rotate according to a set of preset directions. The wafer carrier 106 grasps the backside 104a of the wafer 104 and presses the front face 104b of the wafer 104 against the polishing pad 102. The slurry-supply pipe 110 continuously delivers slurry 110a to the polishing pad 102. Any protruding sections on the wafer react with the chemical reagents in the slurry 110a. The protruding sections are also bombarded by abrasive particles in the slurry 110a and scraped by the roughened surface of the polishing pad 102. Such chemical reaction and physical abrasion continues for some time until the entire wafer surface is planarized.
In a conventional chemical-mechanical polishing system, the wafer carrier and the slurry supply pipeline are separate components on the polishing table so that considerable space above the chemical-mechanical polishing table is occupied. Furthermore, distribution of slurry over the polishing pad by a conventional slurry supply pipeline is usually non-uniform.
Accordingly, one object of the present invention is to provide an integrated wafer carrier structure above the polishing table of a chemical-mechanical polishing device. The carrier structure incorporates a slurry supply pipeline so that the space above the polishing table is less cluttered.
A second object of this invention is to provide an integrated wafer carrier structure for a chemical-mechanical polishing device. The carrier structure incorporates a slurry supply pipeline so that fabrication and maintenance costs are reduced. A third object of this invention is to provide an integrated carrier wafer structure for a chemical-mechanical polishing device. The slurry supply pipeline incorporated with the carrier wafer structure is able to improve the distribution of slurry over the polishing pad of the polishing device.
To achieve these and other advantages and in accordance with the purpose of the invention, as embodied and broadly described herein, the invention provides a wafer carrier structure for a chemical-mechanical polishing device. The wafer carrier structure includes a holder and a slurry supply pipeline. The slurry supply pipeline is mounted on the side of the holder with the outlet of the pipeline pointing in a direction parallel to the sidewall of the holder.
This invention also provides an alternative carrier structure for a chemical-mechanical polishing device. The wafer carrier structure includes a holder and a slurry supply pipeline. The slurry supply pipeline is mounted on the side of the holder with the outlet of the pipeline pointing in a direction perpendicular to the sidewall of the holder.
In this invention, the wafer carrier and the slurry supply pipeline are integrated together. Hence, more space is available above the polishing table of the chemical-mechanical polisher. Furthermore, both fabrication cost and maintenance cost of the polisher are reduced and uniformity of slurry distribution over the polishing pad is improved.
It is to be understood that both the foregoing general description and the following detailed description are exemplary, and are intended to provide further explanation of the invention as claimed.